Alleviator



W. T. KNAUTH Dec. 21, 1954 ALLEVIATOR 2 Sheets-Sheet 1 Filed Nov. 3,1949 INVENTOR. Zer T. Km ulh If ATTORNEY Dec. 21, 1954 K AUT 2,697,450

ALLEVIATOR Filed Nov. 3, 1949 2 Sheets-Sheet 2 I I /II 12 l5 I4 15 16-17 U INVENTOR.

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-ATTORNEY United States Patent ALLEVIATOR Walter T. Knauth, Houston,Tex. Application November 3, 1949, Serial No. 125,243

2 Claims. (Cl. 138-30) This invention relates to an alleviator, or shockabsorber, particularly adapted for use in connection with fluidconducting pipe lines through which the fluid is forced, in pulsations,by means of reciprocating pumps or other, similar sources of pressure.

The present invention includes certain improvements over the type ofalleviator disclosed in United States Patent No. 2,290,337, issued toapplicant on July 21, 1942.

An object of the invention is to provide an alleviator adapted to beinterposed between the pump and the conducting line, or incorporatedinto the line itself and which is effective to absorb excessivepressures and restore abnormally low pressure and to thus protect theline from the shocks due to variations in pressures.

Another object of the invention is to provide an alleviator of suchconstruction that air or gas may be utilized as a dampening agent toabsorb the shocks and which is also of such construction as to beadapted for use on lines carrying fluids containing abrasive materialsor foreign matter.

A further feature of the invention is to provide an alleviator having anintermediate chamber containing clean operating fluid whereby a valveand seat employed will be operable in clean liquid and where theintermediate liquid acts as a damper.

A still further object is to provide an alleviator wherein theintermediate liquid dissipates heat from the diaphragm resulting fromrapid flexing.

The diaphragm being located between two bodies of liquid, the migrationof gas through the diaphragm will be prevented.

Other objects and advantages will be apparent from the followingspecification, which is illustrated by the accompanying drawings,wherein:

Figure 1 is a side view, partly in section, of the alleviator;

Figure 2 is an enlarged, fragmentary, vertical, sectional view showingthe valve assembly;

Figure 3 is an enlarged, fragmentary, vertical, sectional viewillustrating the mounting of the diaphragm.

Referring now more particularly to the drawings, the

numeral 1 designates the casing as a whole, which, in the presentillustration, is formed with upper and lower chambers 2, 3.

The lower end of the casing is composed of a separate casting, which isfitted to the adjacent part of the casing above and which is securedthereto by an annular clamp 4 which is screwed onto one of said sectionsand which has an inside shoulder 5 engageable against the correspondingexternal shoulder 6 carried by the other section of the casing 1. Thereis a circular diaphragm 7, which is preferably formed of rubber orsimilar material and which spans the lower chamber 3. It has a marginalrib 8 which is clamped between said separate sections of the casing, asshown in Figure 3, the abutting parts of said sections having grooves toreceive said rib so as to anchor the rib against detachment and also toform a leak-proof joint between said parts. Any other suitable type ofdiaphragm may be employed such as an ordinary yieldable partition or adiaphragm in the general form of a bellows could be used.

The diaphragm is preferably annularly corrugated, as is indicated inFigure 3.

As is indicated in Figures 1 and 2, the casing is restrictedapproximately mid-way between its ends, and screwed into the restricted,internally threaded, walls of the restricted area there is an annularvalve seat 9, whose upper end is, preferably, upwardly flared, as shownin Figure 2. This valve seat has a central bearing 10, and there is avalve stem whose upper end works through said bearing, and attached tosaid upper end there is an upwardly opening valve 12 which conforms, inshape, to the seating face of the valve seat so as to open and closesaid seat. The lower end of this stem is attached to said diaphragm.

Spaced beneath the valve seat and anchored to said seat by the tie rods13 there is a disc 14 which is provided with openings 15 distributedthrough the area thereof and has a bevelled margin 16 which fits closelyagainst the inner wall of the chamber 3 when the valve seat is screwedto home position.

The disc 14 has a central bearing 17 through which the piston rod 11works.

The alleviator is connected with the pipe line through the connection 18which is connected into the chamber 3 on the opposite side of thediaphragm 7 from the valve mechanism 9, 12, and bridging the inlet ofliquid through the connection 18 there is a disc 19, which is perforatedthroughout and whose margins are secured to the wall of the chamber 3.

The chamber 3 may be filled with a suitable liquid, and the chamber 2may be filled with air or gas under the required pressure, which may beintroduced into the said chamber through a suitable connection, as 20,which may be opened and closed by means of a valve 21 which is threadedinto the connection 20. Under normal operating conditions, the liquid inthe chamber 3, with the pressure of the air or gas in chamber 2 againstit, will expand the diaphragm to its maximum capacity, thus completelyfilling the chamber 3 with liquid, which should rise above and cover thevalve 12, as indicated in Figure 1.

When there is pressure in the line, the diaphragm 7 will be moved topositively open the valve 12 and to force part of the liquid from thechamber 3. through the valve seat 9 into chamber 2, and the valve 12will be maintained open. When there is no pressure in the line, thediaphragm 7 assumes its normal position, as shown in Figure l, and thevalve 12 seats on the seat 9 after substantially all of the liquid inthe chamber 2 has returned into chamber 3. When the valve has seated onand closed the seat 9 the diaphragm 7 will be protected from theinfluence of any further pressure drop in the chamber 3.

The ordinary pump pulsations will be dampened by the diaphragm 7 actingagainst the liquid in the chamber 3 which in turn acts against the air,gas or other fluid under pressure in chamber 2.

The perforated discs 14, 19 will tend to spread the liquid flowingthrough them, so that the pressure of the liquid through the disc 19will be distributed substantially uniformly throughout the area of thediaphragm, and the liquid in the intermediate chamber 3 will be forcedto pass through the perforated disc or damper 14 to break up anyisolated currents in the liquid to the end that said liquid will bedampened and will flow uniformly through the valve seat against thediaphragm.

The type of alleviator herein described is of very simple constructionand accurate in operation and is especially adaptable for use fordampening pulsations in liquid flowing through a line under pumppressure. The drawings and description are illustrative of what may nowbe considered a preferred form of the invention by way of illustrationonly and not by way of limitation, while the broad principle of theinvention will be defined by the appended claims.

What I claim is:

1. An alleviator for absorbing pulsations and alleviating vibration in apulsating, pressurized liquid line and comprising a casing including twovertically disposed, rigid walled chambers with the lowermost chamberadapted to be connected to said line to provide an inlet extending fromthe path of liquid flow in the line, perforate means across theintercommunication between chambers and a similar perforate means acrosssaid inlet, a flexible diaphragm dividing the lower chamber and formingwith the casing a space on the inlet side of said diaphragm andcommunicating with said inlet, a body of liquid in said lower chamber incontact with the other side of said diaphragm and extending into saidupper chamber. compressed gas in said upper chamber above said liquid,said chambers providing smooth, substantially spherical inner surfaceswhereby, as line liquid flows into said inlet to urge the liquid abovethe diaphragm upwardly, said upper chamber has an increasing gasliquidcontact area to dampen surging of said upper chamber liquid and of saiddiaphragm, and whereby, as said liquid recedes and liquid flowssubstantially uniformly through said upper and lower perforate means,billowing of said diaphragm is reduced as the horizontal cross-sectionalarea of said upper liquid around said diaphragm first graduallyincreases as said diaphragm recedes to pass the central horizontal planeof said lower chamber and then decreases as said diaphragm furtherdescends as said line liquid flows downwardly through said inlet, avalve seat in said casing around said intercommunication above theperforate means therein, a valve to seat in said valve seat, and a valvestem connected at one end to said valve and at the other end to saiddiaphragm and of a length to limit downward travel of said diaphragm toa position above the perforate means in said inlet and to at leastpartially prevent said diaphragm from being drawn and urged into saidinlet perforate means and into said inlet.

2. An alleviator for absorbing pulsations and alleviating vibration in apulsating, pressurized liquid line and comprising a casing including twovertically disposed chambers with the lowermost chamber adapted to beconnected to said line to provide an inlet extending from the path ofliquid flow in the line, perforate means across the intercommunicationbetween chambers and a similar perforate means across said inlet, aflexible diaphragm dividing the lower chamber and forming with thecasing 21 space on the inlet side of said diaphragm and communicatingwith said inlet, a body of liquid in said lower chamber in contact withthe other side of said diaphragm and extending into said upper chamber,compressed gas in said upper chamber above said liquid, said lowerchamber providing a smooth, substantially spherical inner surfacewhereby after line liquid in a pulsation is forced through said inlet toforce said diaphragm and the liquid thereabove upwardly and said liquidthen recedes as the pulsation peak passes and said line liquid flowsdownwardly through said inlet, billowing and surge of said diaphragm isreduced as the horizontal cross-sectional area of said upper liquidaround said diaphrarn first gradually increases as said diaphragmrecedes to pass the central horizontal plane of said lower chamber andthen decreases as said diaphragm further descends as said line liquidflows downwardly through said inlet, a valve seat in said casing aroundsaid intercommunication above the perforate means therein, a valve toseat in said valve seat, and a valve stem connected at one end to saidvalve and at the other end to said diaphragm and of a length to limitdownward travel of said diaphragm to a position above the perforatemeans in said inlet and to at least partially prevent said diaphragmfrom being drawn and urged into said inlet perforate means and into saidinlet.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,154,223 Wade Apr. 11, 1939 2,290,337 Knauth July 21, 19422,342,356 Mercier Feb. 22, 1944 2,394,401 Overbeke Feb. 5, 19462,417,256 Kremiller Mar. 11, 1947 2,446,358 Yates et al. Aug. 3, 19482,563,257 Loukonen Aug. 7, 1951 FOREIGN PATENTS Number Country Date842,835 France June 20, 1939

